Much has been said about the "ultra-cool dwarf star" that is hosting the planetary system, but the noise around it had sort of faded - until now. "Which is about twice as old as the sun in our solar system".

On the other hand, since the planets are so close to the star, they have soaked up billions of years of high-energy radiation, which could have boiled off atmospheres and large amounts of water, researchers said.

"Our results really help constrain the evolution of the TRAPPIST-1 system, because the system has to have persisted for billions of years", said Adam Burgasser, an astronomer at the University of California, San Diego in the US.

Researchers now estimate the star at the heart of Trappist-1 is between 5.4 and 9.8 billion years old, spurring new questions on the orbit stability of the seven planets circling it, and the potential for life to have evolved in this time.

On the other hand, NASA that TRAPPIST-1 planets have lower densities than Earth, so "it is possible that large reservoirs of volatile molecules such as water could produce thick atmospheres that would shield the planetary surfaces from harmful radiation".

At the time of its discovery earlier this year, scientists believed the TRAPPIST-1 system had to be at least 500 million-years-old.

'If there is life on these planets, I would speculate that it has to be hardy life, because it has to be able to survive some potentially dire scenarios for billions of years, ' Burgasser said.

But, two separate studies have now cast doubts on the possibility of life existing on any of the three Trappist-1 planets situated within the star's habitable zone.

The stars are relatively tame so frequent stellar activity in the form of solar flares would not make the planets less hospitable, as is the case with TRAPPIST-1.

While this may be a promising factor in the search for life, it isn't the only thing that must be considered, the researchers explain.

NASA said it's "unclear" what TRAPPIST-1's old age means for the planets' habitability. "The chance that there's no life is probably very small at this point".

TRAPPIST-1 is an ultracool dwarf star, not a yellow dwarf star like the Sun.

The new measurements all indicated that the Trappist-1 star is far older than our sun.